With the advent of digital image capture, many people believed that making movies would become less complicated because the variabilities associated with analog film, such as different types of film, different types of chemical development processes, etc., would not be an issue when working with digital image data. However, contrary to this belief, the rise of digital image capture introduced many other variabilities. For example, camera manufactures have many more options to tweak the image output of digital cameras because the camera itself can process the captured image. In an effort to obtain the best possible image from a particular sensor within a particular camera, a manufacturer typically will tweak various algorithms used within the camera to process the captured image data. As result, the color characteristics of the images output by digital cameras can be dependent on the manufacturer and model of camera. Moreover, in contrast to film, the digital image output by a digital camera can be directly post-processed by digital image processing software. The additional variabilities introduced by digital image capture typically pose no problems to the average consumer. The average consumer owns a single camcorder, for example, and is not concerned that the color characteristics of images produced by his or her camcorder do not exactly match the images of other camcorders made by other manufacturers. In contrast, the variabilities in the color characteristics of images produced by different digital cameras can present several problems for the movie industry.
Movie productions can use several different types of movie cameras, and some large movie productions can use tens of different types of movie cameras. Shots from all or most of the different types of cameras are cut together to make the movie. Like consumer-grade digital cameras, each digital movie camera can produce images with color characteristics that are unique to the particular camera model and manufacturer. Some of the cameras used in movie productions may be expensive, high-end cameras that can capture a large range of detail, for example, a large color gamut. Other cameras used may be inexpensive cameras used to film shots in harsh or dangerous conditions in which a high-end camera is not suited. These inexpensive cameras might capture less detailed, lower-quality images.
Because of the variations in image characteristics of the cameras used to shoot a movie, the shots from each type of camera must be processed differently in order for the final cut of the movie to have a consistent look. The “look” of the movie refers to how the images of the movie appear when viewed, for example, on a screen or a display. For example, do the images appear bright or dark, focused or soft; are the colors saturated or washed-out; do the images have high contrast or a narrow range of contrast, etc.? The responsibility of matching the image characteristics of the shots of a movie to create a consistent look lies with a group of movie industry professionals called colorists.
For any given large-scale movie production, a movie studio may contract with one or more of a handful of companies that provide color services to the movie industry. In order to create a consistent look, a colorist can adjust and trim various image parameters, apply a variety of filters to image data, etc, for example. The process can be repeated for each type of camera used, for example, and the results can be further refined and matched. The process of creating a consistent look can be arduous. Once the colorist has modified the image data to achieve the desired look, image transformation data for each camera is typically captured in the form of a color LUT, which can be used to transform the color characteristics of image data of other shots to achieve the desired look. The color LUT corresponding to a particular camera can then be used to transform other shots from that camera. In this way, variations among the digital movie cameras used during the production of a movie can be minimized such that the shots captured by the cameras can be cut together into a movie with a consistent look. Color LUTs are also used to transform the color characteristics of image data to compensate for variations in the display systems used to view images, e.g., to adjust the look to be better suited to presentation in a movie theater, or displayed on a TV screen.
Colorists can deliver color LUTs to various entities external to the colorist's company, e.g., clients in the movie industry. For example, some clients can be associated with a movie studio, such as movie directors, camera operators, technical experts, etc. Other clients can include, for example, businesses that provide services to the movie studio, such as visual effects, digital mastering, home video mastering, marketing trailers, etc. During movie production, for example, the director needs to review shots in real-time on the set in order to make decisions whether to retake a shot. On the set, shots typically are reviewed on backlit display devices, such as LCD displays. The colorist creates on-set color LUTs for use with the display devices that are on the set, so that the image of the shot that appears on the display device is an accurate representation of how the shot will appear in a movie theater, for example. After filming is completed each day, the shots captured that day can be reviewed in a more controlled environment by, for example, the director and editor. These daily viewings can displayed on, for example, a projector and screen system. A set of color LUTs are created for daily viewings, also referred to as dailies. Likewise, color LUTs are created for other purposes: visual effects LUTs for use by visual effects artists, digital cinema master LUTs for displaying the movie in theaters with digital cinema systems, home-video master LUTs for tweaking the look of the movie in light of the constraints of DVD encoding, trailer LUTs for use by marketing to produce movie trailers, broadcast master LUTs for tweaking the movie for various broadcast standards, high-definition and ultra high-definition master LUTs, etc. In other words, during the course of movie production, post-production, marketing, and distribution, a large number of color LUTs can be created for different purposes and delivered to different entities in the movie industry.
Adding to the complexity, movie productions are often chaotic and unpredictable. Cameras, lighting, or other equipment may fail or not work properly, and variations in weather or other environmental factors may impact critical shots. Some shots simply cannot be shot again, for example, shots that are expensive to set up (perhaps involving pyrotechnics or dangerous stunts), shots that have captured a moment that cannot be reproduced (such as actor's improvisation), shots that have captured a natural phenomenon, etc. For some impacted shots, special color LUTs may be required to correct the look of the shot. In some cases, an exceptionally critical shot could drive a change to the look of the movie, requiring all previously-created color LUTs to be modified or redone entirely.
The complex logistics often required during movie production can also result in demands for new or modified LUTs. For example, a particular on-set display might become unavailable and be replaced with a different display, thus requiring a new color LUT to be created for the new display. The movie production may switch to on-location shooting, and the room used for viewing dailies may have different lighting conditions than expected, thus requiring a new color LUT. A contract with a particular visual effects house may fall through, and a replacement visual effects house may require a different format for the image data, requiring tweaking the visual effects LUTs for the new format.
Finally, the artistic and creative nature of movie making often contributes to demands for new or modified color LUTs. For example, directors and other creative decision-makers often wish to tweak the look of the movie as more and more shots are captured and reviewed. Creative decision-makers may wish to explore various possibilities for the look of the movie. Colorists can receive requests to create multiple alternative looks, and corresponding multiple sets of color LUTs, for review and comparison. For each decision to tweak the look of the movie, the changes may need to be propagated to all color LUTs used throughout the movie production, requiring creation of a large number of new or modified color LUTs.